1. Field of the Invention
The present invention relates to a cutting apparatus, in particular to a cutting apparatus for automatically cutting material into a desired shape, in which a cutting process can be carried out by spreading a first travelling member, a second travelling member and cutting tools mounted on both travelling members in a laterally symmetrical relation, whereby an annular portion can be cut.
2. Description of the Related Art
In various fields a general method, in which parts and articles having a desired shape are cut by a cutting method from a slightly larger material, has been carried out. For example, in the case where shaped window glass used in cars is manufactured, the above described general cutting method has been adopted.
FIGS. 9 to 12 show a cutting process for obtaining the above described shaped window glass used in cars as one example in which a rectangular plate glass 21, having a size large enough to be cut into out two pieces of window glass, is prepared.
At first, as shown in FIG. 9, an inclined cutting line 22 for cutting the rectangular plate glass 21 into two parts is marked on the rectangular plate glass 21, and then the rectangular plate glass 21 is cut into two half pieces 23, 23, as shown in FIG. 10.
Subsequently, as shown in FIG. 11, a cutting line 24 having a profile coinciding with a shape of a deformed window glass is marked on the half piece 23 and a deformed window glass as shown in FIG. 12 is obtained by cutting the rectangular plate glass 21 along the cutting line 24.
As a general method of cutting, a die-profiling method is known in which a die having a shape equal to a finished shape is prepared and a cutting tool is guided along the profile of this die, and according to this method the cutting tool is manually operated to carry out the cutting of the above described shaped window glass.
In the former die-profiling method disadvantages lie in the fact that a die corresponding to a shape to be cut must be prepared every time and the work associated therewith is expensive.
In addition, in the manual cutting method problems have occurred in that the working efficiency is low, the working accuracy is low, and the mass production can not carried out, whereby increased costs are realized. Furthermore, if a profile line is formed in a large plate glass by means of a plurality of cutters at once, the yield is reduced, whereby again, an increase in cost of the product is realized.
Besides, in a cutting method of articles other than the above described window glass, the similar cutting method as above described has been adopted and the similar problems have occurred.